Vibration isolation or absorption?

This is an interesting read

The theory of more stuff.

Vibration isolation in audio is a subject surrounded in mystery half truths and any number of wild theories. As an engineering exercise, the explanation is quite straight foreword and may be explained by the“Theoryof more stuff”.
 

Take a surface, be it the floor or a table, on which your hi fi component is placed and it is desired to reduce the vibration from thesupport to the equipment. The way this is done is to put “some stuff” between theequipment and the supporting surface. There are three possible outcomes.
 

1 The vibration in the equipment is more than the vibration in the support.
This is not possible as if it were; the energy crisis would be solved! More
out than what is put in. Free power forever! Unfortunately, this scenario
contradicts the first and second laws ofthermodynamics, so is not
possible.
 

2 The vibration in the supported equipment will be the same as in the case of no stuff. Thechances of this are one in a million because something has been changed… it may be thesame, but that is extremely unlikely, therefore, the only possibility is,
 

3 The vibration will be attenuated, to a greater or lesser degree, and this is the case.
 

There are many products out there that do in fact attenuate vibration. Be it spikes on glass, wood and slate, aluminium spikes in cups, ball bearings in cups, solid plates separated by compliant sheets, lead, Bluetack, sand, marble, concrete, the list is endless. It is also known that multiple combinations of theabove produce better results because there is morestuff. E.g. multiple platforms stacked really high.
 

The engineering approach is to get the best result in the simplest manner by optimizing the “stuff” and way back about two centuries ago the Victorian engineers came up with thesolution…. the spring! The spring may be anything “springy”, from elastic, rubber, coiled steel, straight steel, air-bladders to flexible wooden strips. As long as it has sufficient spring or compliance, when optimised with an appropriate mass, a mechanical low pass filter is realised.

The ideal is to have the resonant frequency as low as is possible, ideally around 2Hz in both the horizontal and vertical planes and with a damping ratio of about 0.16. This will give an attenuation of about 25dB at 10 Hz increasing at 20dB per decade above. This will ensure excellent isolation for the deleterious audio system vibrations which are from 5Hz to 500Hz.

In all of audio, nothing, and I mean nothing, is easier to test than the effect of vibration on a piece of solid state gear, and yet ... we have zero in terms of verified results.

It’s not hard, vendors. Put a subwoofer next to your preamp and see if it makes a difference.

Of course, tubes are another thing but even those could be measured.

I’m not saying microphonics don’t exist, I’ve definitely heard it. I had a Radio Shack phono preamp that would ring like a bell when struck, probably due to the ceramic caps in the signal path, but today? Meh.

Wake me up when there’s an iota of measured relationship between vibration and output on any piece of modern solid state gear.  Then when you've actually measured that then you can tell me what sound isolation works best.

Erik, have you watched all the videos Max Townshend made and put up on YouTube? Worth your time, at the very least.

https://www.youtube.com/watch?v=OZxi1oZfvDA&pp=ygUNbWF4IHRvd25zaGVuZA%3D%3D

This is a very complex but important subject.

As others have pointed out, whether to absorb or transmit vibration depends on the floor, the equipment and personal preferences. After thirty years of experiments these are my findings:

On speakers. I have gone from spikes to Symposium Svelteshelves first flat on the floor, then on Final Daruma cups and balls to today end up with a cheap set of Chinese springs in cups

On electronic equipment I can’t even remember all the permutations: Sorbothane, then again Darumas, Symposium Svelteshelves, Black Diamond Rcing Cones and today Black Ravioli Big Pads on Gingko Audio platforms

On phono I have used a Townsend Seismic Sink for many years but now prefer spike mounting on a thick, wall mounted acrylic shelf (bearing the scratch marks with philosophic indifference).

In all this journey, two solution stand out: the springs under the speakers resulted in razor sharp soundstaging and lightning fast leading and trailing edges on individual instruments compared to all other solutions.

The Black Ravioli Big Foots are nothing short of sensational: the elimination of power supply as well as air borne vibrations resulted in significant ‘de-sludging’, i.e. an amazing increase of transparency on large orchestral works. It felt that the sound was much less ‘compact’ and closed in.

As always: Enjoy the Music